Adjusting or tuning means for radio frequency apparatus



Jan. 13, 1942. e. ANDRIEU 2,270,156

ADJUSTING on TUNING MEANS FOR RADIO FREQUENCY APPARATUS Filed June 2711940 Zmventor GU/DO ANDR/EU to-and-fro motion or hunting.

Patented Jan. 13, 1942 ADJUSTING ORQTUNING MEANS roa rmnro rasoosncrarraaarcs- Guido Andrleu, Ber

lin, Germany, assignor to Teletunlren Gesellschatt fiir Drahtlose Telegraphie m. b. H., Berlin, Germany, a corporation of Germany Application 4 Claims.

It is known in the prior art to use a motor in:

combination with a bipartite contact segment disk each for switching the motor for clockwise andcounter-clockwise rotation and for disconnection upon the median position being reached between the two contact halves so as to effect press button tuning of an R. F. apparatus to predetermined positions. In lieu of the contact disks there could also be'used cams or drums with spiral slots of varying depth in conjunction each with a control lever and a change-over or reverser switch for the motor.

' The precision of adjustment in arrangements of this nature is so much greater the smaller the range of rotation corresponding to the neutral June 27, 1940, Serial No. 342,645 Germany January 31, 1939 the ratio of 2:1.

recess, said latches being disengagedby the motor shaft by means of a coaxial thrust rod against the force exerted by retractile springs in such a way that, with the motor running, they areunable to drop and engage in the arrester notches.

An exemplified embodiment of the invention is shown in the appended drawing. The'shaft A1 of the rotary gang co'ndensenC of a receiver is in to0th wheel gear relation with the shaft As at Shaft m supports three drums of reduced length T1, T2, T3, each having a slot N1, N2, N3, respectively, in which engage the con- 7 trol pins of. the change-over switches U1, U2, U3,

median position in comparison with the total range of rotation. If this ratio is chosen small, this entails the disadvantage that, especially if the adjusting movement is fast, the neutral median position will be exceeded, in fact, correct adjustment will be reached only afterirepeated certain circumstances this rocking motion may become permanent.

On the other hand, attempts have been made to make the range of rotation of the neutral median position relatively large, and to insure fine and sharp adjustment by the aid of an ac-' cessory arrester or latch mechanism ,in that the contact pin sliding on the contact ring is allowed to drop and engage in an arresting hole in the middle of the insulation disk between the two Indeed, under halves. However, schemes of this nature involve the inconvenience that the arresting or notch means must either be made very shallow, that is, of little depth in order that the motor, on changing to another position, may be able to release and disengage the -arresting means, or that in the other case, on actuation of the next press button the arrester-latch must be lifted clear of the notch by the agency of mechanical force. In the first case theprecision is inadequate, while in the second instance, remote control is impossible; indeed, the press button must be connected with the arresting means by mechanically acting rods.

According to the present invention the arrester or locker means are controlled by the motor in such a way that they will be operative only with the motor current being switched on. More particularly speaking, for a control of the arrester means there is to be used the axial shift oi'the motor shaft occurring on disconnection of the motor current. The ariester means may co t of latches engaging each in an arrester notch respectively. The slots cover one-half of the circumfe"ence of each drum on the left-hand side, and the other half thereof on the right-hand side, while at the transition point thereof there is a stage which corresponds to the median position of the switches. g The shaft A: at the same time is in connection with the motor M0 by means of a disengageable friction clutch or drive. 'When the motor is excited, the rotor is moved out to the right-hand side with the result that the friction gear is engaged. At the same time, the shaft butt As of the rotor causes the thrust rod S with adjuster rings R1, R2, R3, respectively, to be pushed to the right-hand side so that the locker levers H1, H2, H1, are disengaged to the right against the forces of the springs F1, F2, F3. The locker levers carry at their top ends the locker latches or catches'Ki, K2, K3, respectively. These may have the form of slightly coned pins, and they are adapted to engage in suitable arrester holes or' recesses-formed in the drums T1Ta, of which holes only hole L3 is shown in the drawing. Each arrester hole is so arranged that the corresponding latch or pin is located ahead of the hole when the control pin of the corresponding switch (in the present case U3) is in the median position of the control slot (N3) However, notching is possible only when the motor isdisengaged, that is to say, is not excited.

The switches U1, U2, U3 connect the potential of the source of current Q to respective press button switches D1, D2, D3, according to their position with the right-hand rotation winding 1:: or the winding Ll corresponding to counter-clock wise rotation of motor Mo.

The position shown in the drawing is the one for which the switch D3 has been closed. Now, 1

or as clockwise rotation of the motor will be fed with rod s pushed the locking lever H: with latch e K: out of the hole L:- At the same time the friction clutch causes rotation of the shaft A1. The first point reached is the median position of the slot N2. However, inasmuch as it is not D: but Dr that has been closed, the motor continues to revolve; but the latch K: is unable to engage in the corresponding recess of drum T2. It is only a brief instant prior to the median position of the slot Ni being reached that the motor current is broken. The clutch is disengaged and at the same time the spring F1 pulls the latch K1 against the lateral wall of the drum T1. But the momentum inherent in the mechanism continues to revolve the shaft A: a small distance. The sliding locker pin K1 soon after reaches the corresponding arrester notch or hole (not shown) and engages therein, with the result that the mechanism is locked in position.

The accuracy of adjustment in this arrangement is governed only by the play or backlash of the locking" pin in its recess or hole (and this is less than one-tenth of one millimeter), indeed it is independent both of the width of the median position and of the distance of the two springs of the change-over switch. The length of the step in the slot corresponding to the median position must only be chosen in accordance with the momentum of the motor and the locking means, that is, so that the locker pin prior to the proper adjustment being reached, will be set upon the edge of the disk, and that the arrangement will continue to run as far as the proper position.

The press buttons D1 and D1. of course, may be spaced apart at will. The control of the thrust rod S and thus of the locking latches could be accomplished also by a single relay controlling the motor current instead of by the dis engageable rotor shaft of the motor.

I claim: 1. In a tuning control system for radio receivingapparatus and the like, a control shaft, an electric motor for driving said shaft, 9. plurality of contactors for controlling the operation of said motor, a plurality of operating members for said contactors mounted on said shaft, a plurality of locking. means one for each of said operating members, each of said locking means cooperating with its associated operating member to lock said member in a predetermined desired position and means controlled by said motor and effective only when said motoris inoperation for rendering said locking means inoperaive.

2. In a control system for radio receiving apparatus and the like, a control shaft, an electric motor for operating said shaft, said motor being 2,270,156 V provided with an axially shiftable motor shaft which is adapted to be shifted from a position of rest to a running position upon the application of a predetermined voltage to the motor and back to the position of'rest upon removal of the voltage, a plurality of contactors for controlling'the operation of said motor, aplurality of operating members one for each of said contactors, said operating members being mounted for operation by said control shaft, locking means acting normally to lock the control shaft in any desired position of rest and means operated by said motor shaft upon displacement of the motor shaft to the running position for rendering the locking means inoperative;

3. In a control system for radio receiving apparatus and the like, a control shaft, an electric motor of the type having an axially shiftable motor shaft which is arranged so as to be shifted from a position of rest to a running position upon energization of the motor and back to the position of rest upon de-energization of the motor.

means associated with both said motor shaft and the control shaft for coupling the motor shaft to the control shaft upon displacement of the motor shaft to the running position to provide for driving the control shaft by the motor, a plurality of contactors for controlling the operation of the motor, a plurality of operating a members for said contactors, said members being adiustably mounted on said control shaft, locking means acting normally to lock the control shaft in any desired predetermined position, and means operated by said motor shaft upon displacement of the shaft to the running position for rendering said locking means inoperative.

4. In a control system for radio receiving apparatus and the like, a reversible motor, a plurality of reversing contactors for said motor, a plurality of operating members for said contactors, a control shaft having said operating members mounted thereon, said motor having an axially shiftable motor shaft which is automatically shifted from a position of rest to a running position upon energization of the motor and back to the position of rest upon de-energization of the motor, means effective only when the motor shaft is in the running position for providing a drivi118. connection between the motor and the control shaft, locking means for said control shaft to lock said control shaft in any desired predetermined position, and means operated by said motor shaft upon displacement of the motor shaft to the running position for rendering said locking means inoperative while the motor is energized whereby the locking means is effective to lock the control shaft only when the motor is in a de-energized state.

. GUIDO ANDRIIU. 

